This invention relates to the removal of undesirable aroma and flavor components from low priced varieties of coffee, primarily the Robustas.
There are basically two major botanical varieties of coffee, Coffea Arabica and Coffea Canephora. The variety Coffea Canephora includes the Robusta coffees, whose quality is generally considered to be lower than that of the Arabica coffees. The Robusta coffees are grown primarily in Africa, Indonesia and Ecuador, and are relatively inexpensive.
There are a number of Arabica coffee varieties, which are generally divided into two major groups, "Brazils" and "Milds". "Milds" are somewhat loosely classified as coffees other than Brazils and Robustas. The "Milds" are grown primarily in Columbia, Central America and the mountains of East Africa and Kenya. They are considered to be premium coffees, and are priced accordingly. Two-thirds of the world's commercial coffee beans are of the Coffea Arabica variety.
Robusta coffees generally produce a strong tasting coffee beverage with good body, but with peculiar, offensive taste and aroma characteristics, which have been described as earthy, bitter, tarry, or rubber-like.
A major reason for the low cost of the Robusta coffees is their bitterness and their unpleasant aroma when brewed. Robustas contain about twice as much caffeine as Arabicas, but this is not the sole reason for their bitterness. The odor sensation that occurs in the nasal passages when the coffee is brewed, smelled, inhaled or ingested is the primary reason for rejecting the Robustas as being a "good cup of coffee". For an analysis of the flavor characteristics of the Robustas and the "Milds", see the Tea and Coffee Trade Journal, 122, 30-36 (1962).
Robusta coffees are almost never used by themselves as roast and ground coffees, but are often blended with Arabicas to provide body and for economic reasons. Because of the taste and aroma of the Robusta coffees, they generally comprise no more than about 15% to 25% of roast and ground coffee blends. Instant coffees typically contain somewhat more Robusta than do roast and ground blends.
It is an object of this invention to improve the flavor of roast and ground coffee, especially low grade coffees of the Robusta variety, by removing the objectionable tarry, earthy and bitter flavor notes.
It is also an object of this invention to improve the aroma and flavor of a beverage made from roast and ground Robusta coffee beans.
Still another object of this invention is to produce an economical roast and ground coffee blend containing a major portion of Robusta coffee and a minor portion of Arabicas, and which has a taste comparable to more expensive coffee blends containing a minor portion of Robustas and a major portion of Arabicas.
These and other objects are achieved herein as will be seen from the following disclosure.